Why do many recipes suggest adding the oil drop by drop at first when making vinaigrette?

Question

Why do many recipes suggest adding the oil drop by drop at first? Understand the science behind this technique for creating a stable emulsion.

Answer 1

Adding oil drop by drop at the beginning of vinaigrette preparation helps to emulsify the oil and vinegar, creating a stable and creamy dressing that doesn't separate easily. This slow incorporation allows the emulsifiers in the mustard or other ingredients to properly bind the oil and vinegar together.

Detailed Explanation:

Vinaigrette is an emulsion, a mixture of two liquids that don't naturally mix well: oil and vinegar. To create a stable emulsion, you need to disperse one liquid (the oil) into the other (the vinegar) in tiny droplets and prevent them from coalescing back together. This is achieved through mechanical force (whisking or shaking) and the help of an emulsifier, such as mustard, honey, or even egg yolk.

Adding the oil slowly, drop by drop, at the beginning is crucial because it allows the emulsifier to coat each tiny droplet of oil as it's introduced. This coating prevents the oil droplets from clumping together and separating from the vinegar. As the emulsion starts to form, you can gradually increase the rate at which you add the oil, but the initial slow addition is key to a stable and long-lasting vinaigrette. If you add the oil too quickly at the start, the emulsifier won't be able to keep up, and the vinaigrette will likely separate.

Pro Tip:

Use a jar with a tight-fitting lid to make your vinaigrette. This allows you to shake the ingredients vigorously, creating a stronger emulsion. Shaking is often more effective than whisking, especially for larger batches.